Incentives for Solid State Scrap Conversion
There are strong economic as well as ecological incentives favoring development of a process for the direct conversion of machine scrap or swarf into a powder which can be utilized by the ferrous powder metallurgy industry. At Ford Motor Company alone as estimated 105,000 tons of low alloy steel machine turnings are generated by the various manufacturing plants and sold as scrap on the open market, destined to be part of a furnace charge in some ferrous melting operation. Its utility, even as a furnace charge material, is limited by high bulk-to-weight ratios and residual machine oil content. The alloying elements present in most of this kind of scrap represent a valuable resource if they could be economically recovered. In melting operations much of this alloy content is oxidized and lost to slag. The ecological advantages of direct conversion of swarf to powder with no intermediate melting operation stem from use of a cleaner, less polluting process and the theoretical 100% recovery of valuable alloying elements. Economically, direct conversion is also very attractive. Based on current prices for iron powders or prealloyed iron powders and the price of swarf on the open market, a significant differential is available for conversion costs and profit. In spite of these incentives, technological problems exist which have thwarted previous attempts to employ powder made from swarf in standard powder metallurgy sintering operations.